Runnr Review: adidas Ultraboost 21


Runnr Review: adidas Ultraboost 21

A classic fan favorite just keeps getting better and better. Calling on all performance-driven runners and style-conscious sneakerheads. Rejoice! The all-new adidas Ultraboost 21 has finally arrived and this latest iteration, might just be the best one yet. Considered to be significantly different enough from the last version, the new model still retains plenty of bounce with the superb energy return the shoe has always been known for. A gradual shift back to its original running roots while maintaining sustainability efforts, without sacrificing style, was a top priority of adidas for their flagship running shoe. The result? Arguably the most Fresh-looking Ultraboost in years, with the right amount of performance to back it up. Who said looks can’t kill?


Curious to learn more on the iconic shoe’s overall design and performance? Read on to get a closer in-depth look on the adidas Ultraboost 21 (UB21).


What’s New

Boost technology was a game-changer when adidas first introduced it back in 2013. It granted a super-bouncy sensation that enhanced every runner’s overall running experience. Big fans of the Boost midsole foam will be pleased to know that the latest iteration has 6% more Boost packed into it, as compared to its predecessor. This update perfectly aligns with adidas’ current pursuit and goal for the UB21: To create a shoe that can further exemplify what it means to provide incredible energy return.

Another addition to the UB21 is a new LEP torsion control system that is strategically placed underneath the midsole. It is designed to increase responsiveness and to guide the foot through its natural gait cycle, reducing unwanted cases of overpronation from happening.

Finally, a more precise Primeknit+ upper design further enhances movement, complementing well with adidas’ recycled PrimeBlue mesh. 


Sole Unit

Just one look at the UB21, you instantly notice how visibly thick the heel section of the shoe is. This is directly associated with the Boost midsole foam right towards the heel increasing by 6%, for better energy return. As a result, the UB 21 in a US M9 (12 oz) weighs an ounce heavier than the UB 20 (11 oz), with a heel to toe drop of 10mm. This update also gives an instant firm feel upon step-in, a welcome change to make the shoe more responsive while still comfortable enough.

Just right beneath the Boost midsole lies the new LEP Torsion system which extends into both the forefoot and heel. It is a stiff horseshoe shaped plastic insert that reduces the amount of flex at the forefoot by 15%, naturally resulting to more propulsion. This creates a snappier ride, strongly felt upon toe-off.  A stiffer UB also means better midfoot stability, reducing the amount of tension and injuries often associated with running.

The Outsole gets a new look as well, with adidas changing the traction patterns and settling for a much brighter color scheme for this latest model. It has a flatter layout, so a smoother ride transition is expected. Impressive Continental rubber also remains for solid road traction, well suited to both wet and dry conditions.


Upper Unit

A commitment to sustainability continues to factor in adidas’ shoe designs. The upper mesh of the UB21 is made with Primeblue, a high-performance recycled material made in part with Parley Ocean Plastic. Similar to its predecessor, the secure sock-like feel from the lightweight Primeknit upper gives a nice touch to balance foot support and running performance, though can be improved in terms of breathability. Lastly, the iconic adidas Three Stripes stands out in translucent plastic, and an extended heel tab curve benefits the achilles.


Feel and Performance

To help us provide a more in-depth look on the adidas Ultraboost 21, we invited runnrs Jael Wenceslao and Gianna Cantoria to try on a pair of the shoe and give their reviews on the shoe’s overall performance. Here are their takes:


Jael Wenceslao is a 3:01 marathoner. He has qualified twice for the Boston Marathon and last ran in the 2019 edition. He has completed several other World Marathon Majors including New York, Berlin, Chicago and Tokyo, and is an accomplished ultramarathoner, having done two 100-mile foot races, as well as the MIWOK 100K in California and Wild Duluth 50K in Minnesota. He also has competed in Ironman Langkawi (Malaysia) and is an ambassador for Simple Hydration, Tailwind and Rudy Project. 



Jael: Most runners dismiss the adidas Ultraboost (UB), opining that it’s too heavy but I think they miss the point. True, the UB is heavy because it’s meant as a daily trainer - for the easy miles, or those recovery runs. I wear the UB because it is dependable; it’s my workhorse. Moreover, it is durable. I’ve owned plenty of running shoes since 2007 and the UB is arguably the most durable pair. 

The latest iteration of the UB is the Ultraboost 21 (UB21), and it’s built like a tank. In this age of lightweight (yet fragile) speedy shoes, it’s nice to have a pair which you can wear anywhere with confidence and not flinch at the damage the surface inflicts, while protecting your joints. Cement, asphalt, gravel, light trails - I wore them with no hesitation; the UB21 is meant to be abused. 

The UB21 is not designed for hard sessions like tempo runs. Rather, it’s built for majority of the easier runs that take place throughout the week. The upper material is soft and comfortable, hugging my foot well, while the lacing system is the best among the UB models (I’ve always had trouble with the locked down feeling of the UB - but the UB21 is an improvement). My heel stayed in place. The profile is also wide, so major concerns of rolling my ankle disappeared. 

I wore the UB21 twice - a 30-min fast run in BGC at 4:01 pace and an easy 100-min run in Nuvali at 6:16 pace. The fast run was admittedly a bit of a struggle because of the weight of the UB21 (more Boost foam naturally equals a heavier shoe). As for the easy run with the rolling profile of Nuvali, my legs weren’t that battered by the concrete roads (the UB21 has the thickest amount of Boost foam in my opinion among the UB models). 

Let’s be real - a runner should run easy 80 percent of the week, while your hard runs are at 20 percent. So 80 percent of the week, call on the UB21 as your trusty best friend. And with the insane amount of Boost foam on it, you know it’ll last a long time. I know I’ll have my new best friend on speed dial for those 2-hour easy runs in Nuvali!



Gianna is a running enthusiast who joined her first ever 10KM race in 2019. She recently joined her first marathon - Virtual Cebu Marathon 2021 and she plans to one day join international races. Currently, she runs an average of 4x a week and is an active member of the #WeKenRun speed trainings of Coach Ken Mendiola. She believes that running is for anyone who seeks to be stronger and healthier, physically and mentally.


Gianna: I have constantly been in search for the perfect shoe that best complements my running gait and preference. When I started running back in 2019, I got my first ever pair of trainers from Runnr, the adidas Ultraboost (UB) 19. It was then followed by the 2020 iteration and while I love my UB 19 and 20, I found myself experimenting with other running shoe brands, seeking for the shoe most well-suited to me in terms of feel, look and performance.

When the UB 21 was officially announced, the shoe’s fresh look and bright colorway instantly replicated that “love at first sight” feeling my old UB 19 gave me. The design resonated with my personal preference, inspiring me to go lace up by just looking at it. It’s visually appealing for both running and casual wear, a head-turner kind of pair that is sure to up anyone’s running photo game. I was convinced! I had to try out what is arguably adidas’s best-looking running shoe in recent memory.

The first fitting felt amazing (fits true to size) when I finally got the chance to try on a pair at runnr. My foot type is on the wider side and the UB 21, even with a sock-like fit, is very breathable and doesn’t compress my feet to the point of discomfort. Upon my first steps with the shoes, it felt cushioned yet firm despite the higher heel stack due to the added 6% Boost. The laces also needed no double tying unlike previous versions while the sole stands out with its vibrancy and gives off a feel-good vibe. Lastly, the Parley ocean plastic mesh made of sustainable recycled materials is an appeal in its own.

Running with this pair was such a pleasant surprise! I took it for a 5km break-in at easy pace and the responsiveness and heel support from the added boost was incredible! The shoes propelled me forward, a welcome surprise that was missing from my previous UBs. Upon taking it for longer runs (10k and 14k), and mixing in some speedwork and hill reps, I found my feet and legs still well-supported without any major episodes of discomfort occurring. I even expected a few blisters post break-in run similar to my old UBs, but I finished without a scratch!  

However, the shoes started feeling more awkward the faster I ran them in. Wasn’t that big of a surprise though, considering how the UB is really designed to be a daily trainer and not for fast runs. The overall weight may also have been a factor but personally, I don’t find the shoes heavy. The added Boost weight became quite evident during my speed drills and hill reps, but it’s something I’m willing to carry in exchange for better energy return.

My personal experience with UB 21 has made my search for the perfect pair over, well at least for now. For the first time in a while, I have a pair of trainers that is close to the feel, look and performance I’m actually looking for. I definitely see them as my go-to daily running companion, helping me further build my up endurance and running economy towards becoming a better (and ultimately faster) runner!


Looking to #RiseUpAndRun with superb energy return? Run today with the all-new adidas Ultraboost 21! Head on over to your nearest runnr store or shop here at to score a pair, and for your other much needed running essentials! Make sure to follow us on Facebook and Instagram as well, for more shoe reviews and to stay up-to-date with all the latest on anything and everything runnr, the leading running specialty store in the Philippines. Happy running!



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